Why do riders blackout while riding (medically confirmed as not related to alcohol, drugs or seizures)?
Has anyone seen/found documentation to give evidence as to why a rider might nod out or at least become groggy and crash under virtually perfect conditions? Where it is proven that no drugs, alchohol, seizure or head impact prompted, nor rider fatigue or stress at significant levels.
The only thing I've found so far is a much disputed theory about oxygen deprivation in full coverage helmets. Not that the rider passed out from the CO-2 buildup, just that the reduced oxygen might produce a lack of judgement or reduced reflexes / concentration. In particular this theory is considered for cooler weather wherein the rider would be more bundled up and helmet vents closed to stay warm.
Appreciatte any constructive response(s) on this